Репозиторий Университета

© 2017 EDIZIONIMINERVAMEDICA. BACKGROUND: Goals of vestibular schwannoma (VS) microsurgery are maximal resection, facial nerve (FN) preservation and in selected cases, hearing preservation (HP). Postoperative HP rates are related to clinical and radiographic factors: Size of tumor, preoperative hearing, hypertension, diabetes, and presence or absence of preoperative tinnitus. In this retrospective review we evaluated the influence of preoperative tinnitus on HP after VS surgery in patients with preoperative socially useful hearing (SUH). METHODS: Twenty-five patients with SUH underwent VS micro neurosurgery by retrosigmoid (RS) approach. Selection criteria were pure tone audiogram ≤50dB loss and speech discrimination score >50% (50/50 criterion, AAO-HNS class A-B). In relation to maximum diameter, we identified two size-groups: 1) group A ≤2cm (13 cases); 2) group B >2cm (12 cases). HP attempt was assisted by intraoperative ABR evoked by LS CE-Chirp® (Interacustics, Middelfart, Denmark) acoustic stimuli. RESULTS: Mean age was 44.3 years (20-64); average maximum diameter 2,0cm (0,8-4). Preoperative tinnitus was present in 10 patients (40%): All of them had a Class B-hearing. Total and nearly-total (>95%) resection was possible in all. Mortality and major morbidity were zero. In all, facial nerve (FN) was anatomically and functionally preserved; in 10 an incomplete FN deficit was followed by complete recovery within 2-8 weeks. At a follow-up ranging from 8 to 17 months (average 12.7 months), socially useful hearing (SUH) preservation rate was 52%, with significant differences in relation to size: 61.5% group A and 41.7% group B (P=0.014). Postoperative AAO-HNS C (serviceable) hearing was observed in 36%, deafness in 12%. At last follow-up, among the 10 patients with preoperative tinnitus 6 worsened from Class-B to Class-C, 3 remained in Class-B, and one was deaf. As regards SUH preservation, 3 of 10 patients with preoperative tinnitus and 10 of 15 without it remained in Class-A-B (P=0.006). CONCLUSIONS: Microsurgery represents the first therapeutic option for small growing VS with SUH. Our data confirm that key-hole RS rea moval of VS with intraoperative LS-CE-Chirp ABR monitoring allows good rate of SUH preservation, especially maximum diameter does not exceed 2cm. Preoperative tinnitus seems to indicate a lower hearing reserve and predicts a lower likelihood of HP.

PURPOSE: To analyze the condition of the lacrimal gland in patients confirmed to have sarcoidosis. MATERIAL AND METHODS: The study included 46 patients (92 orbits) with verified diagnosis of systemic sarcoidosis that were examined during the period of 2009 to 2014. The age of patients ranged from 23 to 65 years and the average was 45.1 years. Among the examined patients, 66% were female and 34% male. In all patients, the diagnosis was verified according to modern criteria. RESULTS: Acoustic structure of 46 lacrimal glands of patients with systemic sarcoidosis (92 orbit), and lacrimal glands of 30 healthy individuals (60 orbits) were examined. In-depth in vivo examination of morphological changes was done using 'advanced' analysis of three-dimensional images. CONCLUSION: The analysis of a large number of studies devoted to changes in the lacrimal glands caused by sarcoidosis revealed a difficult problem: are there any differences between isolated involvement of the lacrimal gland tissue and the defeat of various organs and tissues? For now, the question remains unanswered.

© 2017 Elsevier B.V. The purpose of this work was to investigate experimentally the capacity of passive acoustic thermometry (PAT) for the reconstruction of 1D, time-variable distributions of the internal temperature. Because in the PAT a noise signal is measured, a considerable integration time (about one minute) is required to attain an acceptable error level (0.5–1 K). To optimize the time, an algorithm was proposed to take account of the fact that the temperature satisfied the heat equation. The problem was reduced to that of determining two parameters (initial temperature and thermal diffusivity) of the object under study. The desired parameters were considered constant and were not determined anew after each measurement; instead, their values were refined using all the previous measurements. The proposed algorithm was tested experimentally (where the temperature was reconstructed in a model object, a slab of polytetrafluoroethylene) and investigated by means of computer modeling. The duration of one measurement was about 5.5 s. As a result, an error of the temperature reconstruction of about 0.5 K, acceptable for medical applications, was attained after 30–60 s (depending on the depth) from the beginning of the measurements. After that, temperature distributions can be reconstructed after each measurement without loss of the reconstruction accuracy. The proposed method can be used to control the temperature under a local hyperthermia, lasting 1 min and more, of the human body.